Results of a study examining the use of onabotulinumtoxinA in pediatric patients with overactive bladder

There is a lack of approved treatments for pediatric patients with overactive bladder (OAB) with inadequate response to anticholinergic therapy. OnabotulinumtoxinA 100U is approved to treat OAB in adults based on data from randomized, pivotal trials.

To investigate the efficacy and safety of onabotulinumtoxinA treatment of OAB in children aged 12-17 years who were not adequately managed with anticholinergics.

In this multinational, multicenter, randomized, double-blind, parallel-group, multiple-dose study (NCT02097121), pediatric patients with OAB were randomized 1:1:1 to receive onabotulinumtoxinA 25U, 50U, or 100U (≤6 U/kg). Patients could request retreatment starting at week 12. The primary endpoint was change from baseline to week 12 after treatment 1 in daily frequency of daytime urinary incontinence (UI) episodes. Safety assessments evaluated treatment-emergent adverse events (TEAEs).

Of 68 screened patients, 55 received ≥1 treatment. Mean age was 14 years; 85.5% of patients were female. At week 12 after treatment 1, least squares mean change from baseline in daily frequency of daytime UI episodes showed a numerically greater reduction in the 100U arm (-2.4) versus the 25U arm (-1.4; P = 0.38), with a significant within-group change from baseline in the 100U arm (P = 0.0027). Achievement of treatment response was significantly greater with onabotulinumtoxinA 100U vs 25U (Figure). Median time to request retreatment was ≥16 weeks in all groups. The most frequently reported TEAEs were nasopharyngitis (10.9%) and urinary tract infection (UTI; 10.9%). Urinary retention was observed in 1 patient during treatment cycle 2; there were no serious TEAEs of UTI or urinary retention. Throughout 2 additional treatment cycles continued efficacy for the 100U dose arm was observed along with a consistent safety profile.

Change in daily frequency of UI episodes at week 12 in treatment cycle 1 was not significantly different between arms. However, ≥50% response rate was significantly higher with onabotulinumtoxinA 100U versus 25U. Enrollment challenges that lowered the sample size could have reduced statistical power. Also, the lack of a placebo arm and the observed benefit with the 25U comparator limited interpretation.

OnabotulinumtoxinA injections were well tolerated in children with OAB at all doses studied. Although the primary endpoint was not met, the significantly greater treatment response rate observed with onabotulinumtoxinA 100U versus 25U suggests additional benefit of the higher dose, without additional safety concerns.